The present invention relates to use of a leader in automatically developing photographic films, and more specifically to a decoupling means for automatically decoupling such a leader from a film to which it is attached.
After a customer has exposed a roll of photographic film, the customer takes the film to a photofinisher to obtain photographs of the images captured on the film. In order to develop the film, the photofinisher passes the filmstrip through a series of liquid baths that typically include a developer, a bleach/fix and a stabilizer. The film is then dried and used to create photographs or digital images.
One method of passing the film through the various baths is to attach a leader card to the lead end of the film and pull the leader card through the baths. The leader is a flexible synthetic resin sheet formed with a plurality of equally spaced holes arranged in a feed direction. The holes are adapted to engage a leader feed sprocket provided in the film developing unit. As the leader card is pulled through the baths, the film is towed behind the leader card and is therefor exposed to the baths.
If a film should separate from the leader and sink into a developing tank filled with developing solution, the film has to be taken out of the tank, which interrupts the developing operation. This work is troublesome and time-consuming. Also, there is the possibility that the film might be inadvertently exposed to light while taking it out of the developing tank. In order to prevent such an accident, every film has to be securely connected to a leader.
Various methods are used to attach the filmstrip to a leader card. Tape is commonly used to hold the filmstrip to the leader card But splicing tapes are difficult to handle because they have to be applied to the films and the leader while placing them on a special workbench to couple them together with high accuracy. Moreover, it is troublesome to detach the tapes from the films and the leader after developing films. The use of such tapes is also disadvantageous from an economical viewpoint because they are not reusable.
Filmstrips attached to a leader card with tape are removed by cutting the end of the filmstrip closest to the leader card and peeling the tape off the card and filmstrip. This process is messy but doable for manual handling. If the process is automated, the cutting action is clean but removal of the tape is complicated. U.S. Pat. No. 5,608,487 discloses a method to remove leftover tape from a leader card, but removing the tape from the film without damaging the film is difficult.
Some leader cards use tabs or tongues to clip the filmstrip on to itself, eliminating the use of tape. An example of a leader card that uses a tab type clipping method is disclosed in U.S. Pat. Nos. 5,652,941; 5,376,986; 5,381,204; and 5,463,411. FIGS. 34-37 show an example of the leader card described in the ""941 patent, which provides a coupling structure capable of coupling films to a leader with high reliability. As shown, a leader 1 includes a flexible leader body formed of a synthetic resin sheet. It is formed with a plurality of holes 2 arranged along a feed direction at equal intervals. The leader 1 is fed in one direction by engaging a sprocket (not shown) in the holes 2 and rotating the sprocket. The leader body has holes 4 in the rear portion thereof on both sides of the holes 2. A film 3 can be inserted in each hole 4.
The holes 4 have a width substantially equal to the width of film 3. By inserting the films 3 into holes 4, both edges of the films 3 abut both sides of the holes 4. Clips 5 are superimposed on the leader body 1 to cover the respective holes 4. The clips 5 are fastened to the leader 1 by bonding or fusing. Each clip member 5 has a window 6 that registers with the hole 4. Resilient protrusions 7 are formed on the front edge (with respect to the feed direction of the leader) of each window 6. The protrusions 7 extend across the holes 4 along the feed direction of the leader 1 so that their free ends are supported on the leader body near the rear edges of the holes 4.
The leading end of each film 3 is provided with holes 9. The protrusions 7 are adapted to engage in the holes 9, respectively. In order to connect the films 3 to the leader 1 accurately with little possibility of the films 3 inclining relative to the leader 1, each film 3 should have more than one hole 9 to receive a plurality of protrusions 7. By inserting the leading end of each film 3 into the hole 4 and the window 6, the protrusions 7 are deflected upwardly by being pushed by the leading end of the film 3 as shown in FIG. 36.
When each film 3 is inserted until its holes 9 face or oppose the protrusions 7, the protrusions 7 will be urged into the holes 9 due to their own resilient restoring force. By pulling back the film 3 in this state, the protrusions 7 are allowed to return to their original rest positions. The film 3 is thus coupled to the leader 1 as shown in FIG. 35. In the above manner, each film 3 can be automatically coupled to the leader 1 by pushing each film into the respective hole 4 by a predetermined distance and then pulling the film back. Once coupled to the leader 1, the films 3 are rigidly connected to the leader 1 with the free ends of the protrusions 7 supported on the rear edges of the holes 4 so that they will not be deflected downwardly. The films 3 are then fed, guided by the leader 1, into the film developing unit for development.
To detach films 3 from the leader after development, the films 3 are pushed forward, typically by hand, to raise the protrusions 7 until they completely disengage from the holes 9, and then the films are pulled back. In their rest positions, the protrusions 7, formed integrally with the clip members 5, are flush with the top surfaces of the clip members 5 fastened to the leader body 1. Thus, the protrusions 7 are less likely to be deformed by being caught by e.g. fingertips than protrusions directly fastened to the leader body 1. Nonetheless, hand removal is an inexact process that can lead to reliability problems in actual operation. Moreover, even though removing a filmstrip from a leader card with tabs is easier both manually and automatically, depending on the method used, damage to the end of the film and breakage of the leader card tabs occur.
An object of this invention is to provide a decoupling means for decoupling a film from a leader, which enables the film to be disconnected from the leader easily, reliably and automatically.
The present invention is directed to overcoming one or more of the problems set forth above. Briefly summarized, according to one aspect of the present invention, apparatus for removing a film strip from a film leader card includes (a) a feed section for holding the film leader card stationary in a first predetermined position with the film strip attached via protrusions to a film clip, said feed section having an entry port through which the film leader card is fully inserted in a forward direction with the film strip extending in a backward direction outward through the entry port; (b) means for forming a loop in the film that is folded underneath the film leader card in order to rotate the end of the film strip away from the film clip on the opposite side of the film leader card, thereby causing the film strip to de-tension from the protrusions; (c) a pinch roller assembly; (d) a detach mechanism for engaging the loop and extending it further under the film leader card toward, but not contacting, the pinch roller assembly, said detach mechanism including cams for further rotating the film strip until it is completely inverted and oriented in the forward direction, said cams holding the end of the film strip in place against the film leader card; (e) means for driving the film leader card in the backward direction toward the entry port until the film strip extends further through the film clip, at which point the film leader card is locked into a second predetermined stationary position; (f) means for further rotating said detach mechanism until the film strip is immovably engaged with the pinch roller assembly; (g) means for driving the film leader card forward away from the entry port until the film strip is disengaged from the film clip; and (h) means for releasing the detach assembly from the pinch roller assembly so that the film strip may be removed from the film leader card through the entry port.
A mechanism is thus provided which removes a filmstrip from a leader card. This eliminates the operator from the task and provides an automatic means to prepare the filmstrip for feeding into another process such as digital scanning. The leader card tab is configured to accept either 35 or 24 mm filmstrips, thus eliminating the need for two different cards. The removal method does not damage the film or leader card. The removal mechanism described is for removing two filmstrips from a single leader card. The same principle can be used to remove a single filmstrip from a leader card, as well as a single filmstrip from a narrow (single lane) leader card. The claims are intended to cover variations and modifications of the invention, including its application to single filmstrips as well as to multiple filmstrips.
The technical advantage of this invention is that it provides a decoupling means that enables a film to be disconnected from a leader easily, reliably and automatically.